Understanding electron transport mechanisms in monolayer Mo S 2 transistors: Impact of lattice phonon scattering and localized charge traps

Monolayer molybdenum disulfide ($\mathrm{Mo}{\mathrm{S}}₂$) is a prominent two-dimensional semiconductor material known for its high theoretical intrinsic mobility. However, when implemented in transistors, the mobility significantly decreases. To investigate the mechanisms behind this reduction, several theoretical models have been developed to correlate device mobility with temperature. Despite these efforts, the accuracy of existing models remains limited due to the simplified calculation for lattice phonon scattering limited mobility (${\ensuremath{\mu}}_{\mathrm{ph}}$) and lack of appropriate temperature consideration for the localized charge trap (LCT) effect. In this paper, we present a theoretical model to address the mobility degradation in monolayer $\mathrm{Mo}{\mathrm{S}}₂$ transistors by thoroughly reevaluating ${\ensuremath{\mu}}_{\mathrm{ph}}$ and the LCT effect. The temperature and electron concentration dependence of ${\ensuremath{\mu}}_{\mathrm{ph}}$ was calculated with full ab initio scattering rates in the Boltzmann transport equation framework. Additionally, the temperature-dependent parameters (energy range and density of LCT) were proposed to evaluate the LCT effect rationally. Our model accurately fits various electron transport mechanisms for monolayer $\mathrm{Mo}{\mathrm{S}}₂$ transistors, particularly those dominated by lattice phonon scattering or dominated by LCT effects. The validation and broad applicability of the model offer a robust approach for quantitatively analyzing the electron transport mechanisms of monolayer $\mathrm{Mo}{\mathrm{S}}₂$ transistors.